The number of allergic patients to a variety of allergens is rapidly increasing in these days. This is attributed to the large consumption of protein due to the modernization of eating habit and complex combinations of various other factors that cause numerous substances existing in the living environment to convert to allergens.
A rapid increase of food allergy to wheat and other cereals is also noteworthy. In order to avoid food allergy, it is attempted to restrict or prohibit the ingestion of the relevant food item. In the case of processed foods serving as the staple diet like bread, however, it is difficult to restrict or prohibit ingestion.
In general, it is very difficult to make bread using gluten-free cereal flours such as rice flour and buckwheat flour. When dough is fermented with yeast, in the case of dough using wheat flour or rye flour containing gluten (i.e., protein consisting of chemically combined gliadin and glutenin), the carbon dioxide gas generated by fermentation is retained by the gluten so that the gluten network is extended and the dough rises. In the case of dough using gluten-free cereal flour, the carbon dioxide gas generated by fermentation is not retained within the dough so that the dough does not efficiently rise.
Then one approach of making bread using gluten-free cereal flour is by adding gluten extracted from wheat flour to the gluten-free cereal flour so that the bread becomes voluminous, as described in JP-A 2003-304801. Regrettably, wheat allergic patients cannot eat this bread because the gluten added contains a protein acting as an allergen.
It is also known from JP-A 2003-169593 to make bread using the gluten or wheat flour from which the protein acting as an allergen has been removed by a special treatment. Since it is unlikely that the protein acting as an allergen is removed in its entirety, those patients having strong allergic response cannot eat.
For making bread for allergic patients without using wheat flour or gluten extracted therefrom, the use of water-soluble cellulose ether and isagol (or psyllium) so as to render the bread voluminous is known from Carbohydr. Poly., 25, 337 (1994). It is also known to add water-soluble polysaccharides such as guar gum and xanthane gum for the same purpose.
The bread made using isagol or water-soluble polysaccharides has a certain volume, but a hard crust, giving a disrelish to the mouth. When water-soluble polysaccharides are added, the crumb is elastic enough to give a rubber-like mouthfeel. When food fibers like isagol are added, the crumb is very tender and non-elastic, giving a mouthfeel far different than bread. Due to poor moisture retention, the bread becomes dry and crumbly with the lapse of time from baking, suddenly losing a mouthfeel.
For isagol, there are allergic crises and sufficient data to insure safety have not been reported. Thus, there is a need for substitute additives for isagol.
On the other hand, for the purposes of expanding the consumption of rice, increasing the domestic food supply and solving the future short-of-provisions issue, it has been sought to establish a method of making bread using rice flour. It is believed that the bread made of cereal flour other than wheat flour (e.g., bread made of rice flour) gives a unique, gently moist, smooth-to-the-throat mouthfeel different than the traditional bread and will appeal to the people other than the wheat allergic patients. There exists a demand for a method of making bread using gluten-free cereal flour such as rice flour.